Anatomical model displaying

ABSTRACT

Systems and methods of automatically controlling, on a graphical user interface used by a physician, display views of an anatomic structure of a patient. Such systems and methods of automatically controlling display views of an anatomic structure of a patient can facilitate visualizing a position of a medical device relative to the anatomic structure during a medical procedure directed to the anatomic structure. In certain implementations, the systems and methods of the present disclosure provide automatic display views of a cardiac catheter relative to a three-dimensional model of a patient&#39;s heart cavity during a medical procedure such as cardiac ablation.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims the benefit under 35 U.S.C. § 119(e) of U.S.Prov. App. No. 62/330,910, filed May 3, 2016, U.S. Prov. App. No.62/337,541, filed May 17, 2016, U.S. Prov. App. No. 62/338,068, filedMay 18, 2016, U.S. Prov. App. No. 62/357,600, filed Jul. 1, 2016, U.S.Prov. App. No. 62/367,763, filed Jul. 28, 2016, with the entire contentsof each of these applications hereby incorporated herein by reference.

This application is also related to the commonly-owned U.S. patentapplication filed on even date herewith and having Attorney DocketNumber AFRA-0004-P01, entitled “MEDICAL DEVICE VISUALIZATION,” theentire contents of which are hereby incorporated herein by reference.

BACKGROUND

Three-dimensional models are sometimes used to assist in placement oruse of devices when such placement or use is not easily observable orpractical. For example, in medical procedures, three-dimensional modelsare used to assist in the placement and use of medical devices as partof diagnosis or treatment of patients. An example of a medical procedurecarried out with the assistance of the three-dimensional model is theuse of radio frequency (“RF”) catheter ablation to form lesions thatinterrupt abnormal conduction to terminate certain arrhythmias in theheart.

SUMMARY

The present disclosure is directed to devices, systems and methods ofautomatically controlling, on a graphical user interface, display viewsof an anatomic structure of a patient to facilitate, for example,visualizing a position of a medical device relative to the anatomicstructure during a medical procedure performed on the anatomicstructure. For example, the devices, systems and methods of the presentdisclosure can be used to provide automatic display views, on agraphical user interface, of a cardiac catheter (e.g., an ablationcatheter) relative to a three-dimensional anatomical model of apatient's heart cavity during a medical procedure such as, for example,cardiac ablation. As compared to manually controlling display views of athree-dimensional anatomical model during a medical procedure, it shouldbe appreciated the automated visualization according to the devices,systems, and methods of the present disclosure can improve theefficiency of medical procedures and, additionally or alternatively,reduce the need for communication between a physician (in a sterilefield) and a technician (outside of the sterile field) regardingorientation of the three-dimensional anatomical model on a graphicaluser interface used by the physician during the procedure.

According to one aspect, a method includes 1. A method comprisingobtaining a three-dimensional model of a heart cavity of a patient,receiving a signal indicative of a location of a catheter in the heartcavity of the patient, determining at least one geometric feature of thethree-dimensional model, determining a display view of thethree-dimensional model of the heart cavity based at least in part onthe location of the catheter in the heart cavity, on one or moreprevious locations of the catheter in the heart cavity, and on thegeometric feature of the three-dimensional model, and displaying, on agraphical user interface, the display view of the three-dimensionalmodel of the heart cavity.

In some implementations, receiving the signal indicative of the locationof the catheter in the heart cavity can include receiving a signalindicative of contact between the catheter and the heart cavity. Forexample, the signal indicative of contact can be a signal indicative offorce between the catheter and the heart cavity.

In certain implementations, determining the at least one geometricfeature can include calculating, in the three-dimensional model, asurface-normal direction in an area of the heart cavity local to thelocation of the catheter.

In some implementations, determining the at least one geometric featurecan include determining a thinnest direction of the three-dimensionalmodel.

In certain implementations, determining the at least one geometricfeature can be based on determining a bounding box with the smallestvolume that contains the three-dimensional model. For example,determining the at least one geometric feature can include generatingthree scalar values representing a normalized length of the bounding boxin the direction of each respective orthogonal vector of a coordinatesystem of the bounding box and, based on a comparison of the threescalar values to one another, selecting a direction corresponding to oneof the orthogonal vectors.

In some implementations, the method can further include determining atleast one visualization preference of the three-dimensional model,wherein determining the display view is further based at least in parton the at least one visualization preference. For example, the at leastone visualization preference can include a preferred orientation of thethree-dimensional model. Additionally, or alternatively, determining theat least one visualization preference is based at least in part on areceived user input.

In certain implementations, determining the display view of thethree-dimensional model can be based at least in part on the receivedlocation signal over a period of time. For example, the received signalindicative of location of the catheter can be a time-varying signal,receiving the signal indicative of the location of the catheter caninclude processing the time-varying signal, and determining the displayview of the three-dimensional model can be based at least in part on theprocessed, received location signal. As a more specific example,processing the time-varying signal indicative of location of thecatheter can include low-pass filtering the time-varying signal.

In some implementations, determining the display view can be furtherbased at least in part on analysis of the shape of the three-dimensionalmodel of the heart cavity of the patient.

In certain implementations, determining the display view can be furtherbased at least in part on visualization preferences.

In some implementations, determining the display view can be furtherbased at least in part on one or more previously displayed views.

In certain implementations, determining the display view can includeadjusting a size of the three-dimensional model as projected onto aviewing window, and displaying the display view can include displaying aprojection of the three-dimensional model onto the graphical userinterface according to the adjusted size. For example, adjusting thesize of the three-dimensional model projected onto the viewing windowcan be based on at least one of a size of the viewing window on an imageplane, a relative position of the image plane to the three-dimensionalmodel, and a relative position between the viewing window and a centerof projection for the projection of the three-dimensional model.Additionally, or alternatively, at least one dimension of a viewingwindow can be maintained at a fixed multiple of a dimension of theprojection of the three-dimensional model. For example, the dimension isa maximum width of the projection of the three-dimensional model in theimage plane. Further, or in the alternative, determining the displayview can include limiting pitch of the image plane relative to an axisdefined by the three-dimensional model. Still further, or in thealternative, determining the display view can include limiting roll ofthe viewing window relative to an axis defined by the three-dimensionalmodel. In certain instances, the method can further include, based atleast in part on the received signal indicative of location of thecatheter, determining a displacement speed of the catheter, andadjusting the size of the three-dimensional model projected onto theviewing window can be based at least in part on the determineddisplacement speed of the catheter.

In some implementations, displaying the display view of thethree-dimensional model of the heart cavity can include displaying thedetermined view on a three-dimensional graphical user interface. Forexample, displaying the determined view on the three-dimensionalgraphical user interface can include displaying the determined view inan augmented reality environment. Additionally, or alternatively,displaying the determined view on the three-dimensional graphical userinterface can include displaying the determined view in a virtualreality environment.

According to another aspect, a method includes obtaining athree-dimensional model of an anatomic structure of a patient, thethree-dimensional model including a defined surface. receiving a signalindicative of a location of a catheter in the anatomic structure of thepatient, based at least in part on the location of the catheter in theanatomic structure and on the defined surface, determining a displayview of the three-dimensional model of the anatomic structure, anddisplaying, on a graphical user interface, the display view of thethree-dimensional model of the anatomic structure.

In some implementations, the defined surface of the three-dimensionalmodel can include a surface mesh of the three-dimensional model.

In certain implementations, the defined surface of the three-dimensionalmodel can represent a blood-tissue boundary of the anatomic structure.

In some implementations, determining the display view of thethree-dimensional model of the anatomic structure can be based at leastin part on the location of the catheter relative to the defined surfaceof the three-dimensional model. For example, determining the displayview of the three-dimensional model of the anatomic structure can bebased at least in part on the location of the catheter relative to alocal geometric feature of the defined surface of the three-dimensionalmodel.

According to yet another aspect, a method of displaying athree-dimensional representation of a hollow anatomic structure of apatient includes obtaining a three-dimensional model of the hollowanatomic structure the patient, receiving a signal indicative of alocation of a medical device in the hollow anatomic structure of thepatient, determining a display view of the three-dimensional model ofthe hollow anatomic structure based at least in part on the location ofthe medical device in the hollow anatomic structure and on one or moreprevious locations of the medical device in the hollow anatomicstructure, and displaying, on a graphical user interface, the displayview of the three-dimensional model of the hollow anatomic structure.

In certain implementations, the method can further include determiningat least one geometric feature of the three-dimensional model, whereindetermining the display view can be further based at least in part onthe at least one geometric feature of the three-dimensional model.

In some implementations, the method can further include determining atleast one visualization preference of the three-dimensional model, anddetermining the display view can be further based at least in part onthe at least one visualization preference.

According to still another aspect, a method of displaying athree-dimensional representation of a patient's heart cavity includesobtaining a three-dimensional model of the heart cavity of the patient,receiving a signal indicative of location of a catheter in the heartcavity of the patient, determining a trajectory of display views of thethree-dimensional model of the heart cavity based at least in part onthe location of the catheter in the heart cavity and on one or moreprevious locations of the catheter in the heart cavity, and displaying,on a graphical user interface, the display views of thethree-dimensional model of the heart cavity according to the determinedtrajectory.

In some implementations, the method further includes analyzing the shapeof the three-dimensional model, and determining the trajectory of thedisplay views can be further based on the analyzed shape of thethree-dimensional model. For example, analyzing the shape of thethree-dimensional model can include analyzing a local portion of thethree-dimensional model based on the location of the catheter.Additionally, or alternatively, analyzing the shape of thethree-dimensional model can include analyzing a local feature of thethree-dimensional model based on the one or more previous locations ofthe catheter. Additionally, or alternatively, analyzing the shape of thethree-dimensional model can include analyzing one or more globalfeatures of the three-dimensional model.

In some implementations, the method can further include obtaining one ormore visualization preference, and =determining the trajectory of thedisplay views can be further based on the one or more visualizationpreference. For example, the one or more visualization preference caninclude a preferred orientation of the three-dimensional model.

In certain implementations, determining the trajectory of the displayviews can be further based on one or more previously displayed views.

According to still another aspect, a method of controlling a display ofa three-dimensional model of an anatomic structure of a patient includesobtaining the three-dimensional model of the anatomic structure of thepatient, receiving a signal indicative of a location of a medical devicein the anatomic structure, based at least in part on the location of themedical device in the anatomic structure, selecting a display rule, froma plurality of rules, for specification of an orientation of thethree-dimensional model and an image plane, based at least in part onthe display rule, specifying i) the orientation of the three-dimensionalmodel and ii) the image plane, and displaying, on a graphical userinterface, at least a portion of a projection of the three-dimensionalmodel, in the specified orientation, on the specified image plane.

In certain implementations, the display rule can be based at least inpart on the location of the medical device relative to the anatomicstructure. Additionally, or alternatively, the display rule can befurther based at least in part on one or more previous locations of themedical device relative to the anatomic structure.

In some implementations, the plurality of rules can include a local ruleand a global rule, the local rule can be based at least in part on thelocation of the medical device relative to the three-dimensional model,and the global rule can be based at least in part on the shape of thethree-dimensional model. For example, selecting the display rule caninclude selecting the local rule, the global rule, or a combinationthereof based on a comparison of the location of the medical device to aprohibited region at least partially defined by the three-dimensionalmodel. The global rule can be selected if the location of the medicaldevice is within a boundary of the prohibited region. Additionally, oralternatively, the local rule is selected if the location of the medicaldevice is a predetermined distance beyond a boundary of the prohibitedregion. In certain instances, a combination of the local rule and theglobal rule can be selected if the location of the medical device iswithin a predetermined transition distance relative to the prohibitedregion. For example, a relative weighting of the local rule to theglobal rule can vary (e.g., substantially linearly) as a function of adistance from the location of the catheter to the prohibited region.

In certain implementations, the prohibited region can be at leastpartially defined by a center of mass of a volume of fluid representedby the three-dimensional model. Additionally, or alternatively, theprohibited region can be substantially symmetric about at least oneplane containing the center of mass of the volume.

In some implementations, the prohibited region can be substantiallysymmetric about a superior-inferior axis.

In some implementations, the prohibited region can be a double-infiniteright cone having an opening angle of greater than about 5 degrees andless than about 90 degrees.

In certain implementations, the local rule can include determining alocal direction vector based on the location of the medical device. Forexample, the local direction vector can be based at least in part ondirection vectors normal to a surface of the three-dimensional model inan area local to the location of the medical device. Additionally, oralternatively, based on selection of the local rule, the specified imageplane can be a plane perpendicular to an axis defined by the localdirection vector. Further, or instead, selecting the display rule caninclude limiting pitch of the image plane relative to asuperior-inferior axis. Still further, or in the alternative, selectingthe display rule can include limiting roll of a viewing window relativeto a superior-inferior axis, and the viewing window is in the imageplane.

In certain implementations, the specified image plane can be outside ofa surface boundary of the three-dimensional model.

In some implementations, the specified image plane can be based in parton the direction of the local direction vector.

In certain implementations, specifying the orientation of thethree-dimensional model can include specifying a reference axis of thethree-dimensional model and aligning the reference axis with asuperior-inferior axis defined by the three-dimensional model. Forexample, the method can further include receiving an input indicative ofa predetermined preferred direction of the reference axis. For example,the predetermined preferred direction of the reference axis is asuperior direction of the anatomic structure.

In some implementations, if the global rule is selected, specifying theorientation of the three-dimensional model and the image plane caninclude determining a thinnest direction of the three-dimensional modelof the anatomic structure and specifying the image plane in a planeperpendicular to an axis defined by the thinnest direction. For example,the specified image plane is outside of a surface boundary of thethree-dimensional model.

In certain implementations, displaying the projection of thethree-dimensional model on the graphical user interface can includedetermining a zoom magnitude. For example, at least one dimension of aviewing window in the image plane can be maintained at a fixed multipleof a dimension of the three-dimensional model in the image plane.Additionally, or alternatively, the width of the viewing window can bemaintained at a fixed multiple to a maximum dimension of thethree-dimensional model in the image plane. In certain instances, themethod can further include, based at least in part on the receivedsignal indicative of location of the medical device, determining adisplacement speed of the medical device, wherein determining the zoommagnitude can be based at least in part on the determined displacementspeed of the medical device. For example, determining the zoom magnitudebased at least in part on the determined displacement speed of themedical device can include increasing the zoom magnitude as thedisplacement speed of the medical device decreases.

According to another aspect, a method of controlling two-dimensionalviews of a three-dimensional anatomical model can include generating athree-dimensional model of an anatomic structure of a patient,displaying (e.g., on a graphical user interface) a projection of thethree-dimensional model, the projection on a viewing window of an imageplane, receiving a signal indicative of a location of a medical devicein the anatomic structure, based at least in part on the received signalindicative of the location of the medical device, determining adisplacement speed of the medical device in the anatomic structure, andadjusting a zoom magnitude based at least in part on the determineddisplacement speed of the medical device.

In some implementations, the method can further include displaying anindication of the zoom magnitude on the graphical user interface.

In some implementations, adjusting the zoom magnitude can includedecreasing the size of the viewing window with decreasing displacementspeed of the medical device.

In certain implementations, adjusting the zoom magnitude can includeadjusting a field of view.

In some implementations, adjusting the zoom magnitude can includeadjusting a distance between the image plane and a center of projection.

In certain implementations, adjusting the zoom magnitude can includemoving the viewing window and the center of projection relative to thethree-dimensional model.

According to still another aspect, a non-transitory, computer-readablestorage medium has stored thereon computer executable instructions forcausing one or more processors to obtain a three-dimensional model of aheart cavity of a patient, receive a signal indicative of a location ofa catheter in the heart cavity of the patient, determine at least onegeometric feature of the three-dimensional model, determine a displayview of the three-dimensional model of the heart cavity based at leastin part on the location of the catheter in the heart cavity, on one ormore previous locations of the catheter in the heart cavity, and on thegeometric feature of the three-dimensional model, and display, on agraphical user interface, the display view of the three-dimensionalmodel of the heart cavity.

According to yet another aspect, a system includes a medical device anda medical device interface unit in communication with the medicaldevice. The medical device interface unit includes a graphical userinterface, one or more processors, and a non-transitory,computer-readable storage medium having sorted thereon computerexecutable instructions for causing one or more processors to obtain athree-dimensional model of a heart cavity of a patient, receive a signalindicative of a location of a catheter in the heart cavity of thepatient, determine at least one geometric feature of thethree-dimensional model, determine a display view of thethree-dimensional model of the heart cavity based at least in part onthe location of the catheter in the heart cavity, on one or moreprevious locations of the catheter in the heart cavity, and on thegeometric feature of the three-dimensional model, and display, on agraphical user interface, the display view of the three-dimensionalmodel of the heart cavity.

Implementations can include one or more of the following advantages.

In certain implementations, the display view of the three-dimensionalmodel can be based at least in part on the received location of thecatheter in the heart cavity and on one or more previously receivedlocations of the catheter in the heart cavity. Determining the displayview based on one or more previously received locations of the cathetercan, for example, reduce the likelihood of abrupt and/or largetransitions that can disorient or otherwise distract a physician who isrelying on a representation of the three-dimensional model as part of amedical procedure. Additionally, or alternatively, determining thedisplay view based on one or more previously received locations of thecatheter can reduce, or even eliminate, shakiness that can otherwiseappear in an automated representation of the three-dimensional modelbased on catheter location.

In some implementations, the display view of the three-dimensional modelcan be based at least in part on the received location of the catheterin an anatomic structure and on the defined surface of thethree-dimensional model. Determining the display view based on thereceived location of the catheter and on the defined surface of thethree-dimensional model can facilitate, for example, providingacceptable views of the three-dimensional model as the catheter movesthrough the anatomic structure. As a more specific example, determiningthe display view based on the received location of the catheter and onthe defined surface of the three-dimensional model can provide moreinformation than would be discernible from views of thethree-dimensional model derived from catheter position alone, at leastbecause the display view based on the received location of the catheterand on the defined surface of the three-dimensional model can facilitateviewing the catheter relative to a surface of the anatomic structure. Itshould be appreciated that automated generation of such views of themedical device relative to the surface can be particularly advantageousin medical procedures performed on the surface of the anatomicstructure. That is, in general, providing a viewpoint of thethree-dimensional model that accounts for both the location of themedical device and the surface of the anatomic structure can facilitateproper placement of the catheter, by a physician, along a desired areaof the anatomic surface to be diagnosed and/or treated.

In some implementations, the display view (e.g., a viewing windowdefined in an image plane) of the three-dimensional model can be basedat least in part on displacement speed of the catheter. It should beappreciated that such changes to the display view based on displacementspeed of the catheter can facilitate providing intuitive changes to therepresentation of the three-dimensional model. Such intuitive changescan, for example, reduce the need for manual adjustment of therepresentation of the three-dimensional model during a medicalprocedure.

Other aspects, features, and advantages will be apparent from thedescription and drawings, and from the claims.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic representation of a system during a medicaltreatment, the system including a catheter and a graphical userinterface of a catheter interface unit.

FIG. 2 is a perspective view of an ablation catheter of the ablationsystem of FIG. 1.

FIG. 3 is a schematic representation of a tip section of the ablationcatheter of FIG. 2 in a heart cavity of a patient during an ablationtreatment.

FIG. 4 is a schematic representation of the graphical user interface ofFIG. 1 displaying a projection of a three-dimensional model of thepatient's heart cavity during the ablation treatment of FIG. 3, thethree-dimensional model stored on a storage medium of the catheterinterface unit of FIG. 1.

FIG. 5 is a schematic representation of the projection of thethree-dimensional model of FIG. 4 onto a display view displayed on thegraphical user interface of FIG. 1.

FIG. 6 is a flow chart of an exemplary process of displaying thethree-dimensional model of FIG. 4 onto the graphical user interface ofFIG. 1.

FIG. 7 is a schematic representation of a surface-normal direction in anarea of a three-dimensional model local to a received location of acatheter.

FIG. 8 is schematic representation of bounding box analysis of athree-dimensional model.

FIG. 9 is a flow chart of an exemplary process of displaying thethree-dimensional model of FIG. 4 onto the graphical user interface ofFIG. 1.

FIG. 10 is a flow chart of an exemplary process of displaying athree-dimensional model of an anatomic structure of a patient.

FIG. 11 is a schematic representation of a location of a tip section ofthe ablation catheter of FIG. 2, the location shown relative to thethree-dimensional model of FIGS. 4 and 5.

FIG. 12 is a flow chart of an exemplary process of controlling the sizeof a viewing window of the graphical user interface of FIG. 1.

Like reference symbols in the various drawings indicate like elements.

DETAILED DESCRIPTION

The present disclosure is generally directed to devices, systems, andmethods of controlling, on a graphical user interface (e.g., used by aphysician or other medical personnel), display views of an anatomicstructure of a patient during a medical procedure being performed on theanatomic structure of the patient. For example, the devices, systems,and methods of the present disclosure can be used to visualize aposition of a medical device during a medical procedure being performedon the anatomic structure. By way of non-limiting example and for thesake of clarity of explanation, the devices, systems, and methods of thepresent disclosure are described with respect to visualization of acardiac catheter inserted into a heart cavity as part of a diagnosticand/or ablation treatment associated with the treatment of cardiacarrhythmia. However, it should be appreciated that, unless otherwisespecified, the devices, systems, and methods of the present disclosurecan be used for any of various different medical procedures, such asprocedures performed on a hollow anatomic structure of a patient, inwhich direct visual access to the medical procedure is impracticaland/or can be improved by the use of a model of the anatomic structure.For example, the devices, systems, and methods of the present disclosurecan, additionally or alternatively, be used in interventionalpulmonology, brain surgery, and/or sinus surgery (e.g., sinuplasty).

As used herein, the term “physician” should be considered to include anytype of medical personnel who may be performing or assisting a medicalprocedure.

As used herein, the term “patient” should be considered to include anymammal, including a human, upon which a medical procedure is beingperformed.

FIG. 1 is a schematic representation of a system 100 during a cardiactreatment (e.g., an ablation treatment) being performed on a patient102. The system 100 can include a catheter 104 connected via anextension cable 106 to a catheter interface unit 108. The catheterinterface unit 108 can include a processing unit 109 (e.g., one or moreprocessors), a graphical user interface 110, and a storage medium 113.The graphical user interface 110 and the storage medium 113 can be inelectrical communication (e.g., wired communication and/or wirelesscommunication) with the processing unit 109.

One or more of a mapping system 112, a recording system 111, anirrigation pump 114, and a generator 116 can be connected to thecatheter interface unit 108. The irrigation pump 114 is also removablyand fluidly connected to the catheter 104 via fluid line 115. Thegenerator 116 can be also connected via a wire 117 to a return electrode118 attached to the skin of the patient 102.

The recording system 111 can be used throughout the procedure as well asbefore or after the treatment. The mapping system 112 can be used priorto or during the procedure to map the cardiac tissue of the patient 102and, in the case of an ablation procedure, determine which region orregions of the cardiac tissue require ablation. As described in furtherdetail below, the graphical user interface 110 can be used as part ofdiagnosis and/or treatment of the cardiac tissue of the patient 102 by,for example, displaying a three-dimensional model of a heart cavity ofthe patient 102 with the display automatically changing based on thelocation of the catheter 104 in the heart cavity of the patient 102. Ascompared to systems requiring manual control of a display of athree-dimensional representation of a heart cavity of the patient,displaying the three-dimensional representation on the graphical userinterface 110 based on the location of the catheter 104 in the heartcavity of the patent 102 can reduce the complexity and time required toobtain useful views of the heart cavity.

Referring to FIGS. 1-4, the catheter 104 can include a handle 120, acatheter shaft 122, and tip section 124. The catheter shaft 122 caninclude a proximal portion 126 secured to the handle 120, and a distalportion 128 coupled to the tip section 124.

The tip section 124 can include any portion of the catheter 104 thatdirectly or indirectly engages tissue for the purpose of treatment,diagnosis, or both and, therefore, can include all manner and type ofcontact and/or non-contact interaction with tissue known in the art. Forexample, the tip section 124 can include contact and/or non-contactinteraction with tissue in the form of energy interaction (e.g.,electrical energy, ultrasound energy, light energy, and any combinationsthereof) and/or chemical interaction with tissue. Thus, for example, thetip section 124 can deliver energy (e.g., electrical energy) to tissuein the heart cavity as part of any number of treatment and/or diagnosticprocedures. In certain implementations, such delivery of energy from thetip section 124 to the tissue can be through direct contact between thetip section 124 and the tissue. It should be appreciated that, while thetip section 124 is described as delivering energy to tissue throughcontact, such a description is provided here for the sake of clarity ofexplanation and that the systems and methods of the present disclosurecan be implemented using any number and manner of designs of thecatheter 104, including distal end portions of the catheter 104 that donot engage tissue and/or distal end portions of the catheter 104 thatdeliver other types of energy.

The catheter 104 can further include a magnetic position sensor 130positioned along the distal portion 128 of the catheter shaft 122. Itshould be appreciated that the magnetic position sensor 130 can be anyof various magnetic position sensors well known in the art and can bepositioned at any point along the distal portion 128. The magneticposition sensor 130 can, for example, include one or more coils thatdetect signals emanating from magnetic field generators. As an example,one or more coils for determining position with five or six degrees offreedom can be used. The magnetic field detected by the magneticposition sensor 130 can be used to determine the position of the distalportion 128 of the catheter shaft 122 according to one or more methodscommonly known in the art such as, for example, methods based on usingthe magnetic sensor to sense magnetic fields in the bed and using alook-up table to determine location of the magnetic position sensor 130.Accordingly, because the tip section 124 is coupled to the distalportion 128 of the catheter shaft 122 in a known, fixed relationship tothe magnetic position sensor 130, the magnetic position sensor 130 canalso provide the location of the tip section 124. While the location ofthe tip section 124 is described as being determined based on magneticposition sensing, other position sensing methods can additionally oralternatively be used. For example, the location of the tip section 124can be additionally, or alternatively, based on impedance, ultrasound,and/or imaging (e.g., real time MRI or fluoroscopy).

A three-dimensional model 134 of a heart cavity 132 of the patient 102can be built based on known positions of the tip section 124 of thecatheter 104 in the heart cavity 132 (e.g., prior to application of theablation treatment) and/or based on images of the heart cavity acquiredprior to or during the procedure. The three-dimensional model 134 canbe, for example, an anatomical model of the heart cavity 132 anddisplayed on the graphical user interface 110. In certainimplementations, the graphical user interface 110 can betwo-dimensional, and a two-dimensional representation of thethree-dimensional model 134 can be projected onto the graphical userinterface 110. It should be appreciated, however, that the graphicaluser interface 110 can additionally or alternatively include athree-dimensional display including, for example, an augmented realityenvironment and/or a virtual reality environment. Further, because theposition of the tip section 124 is known, the position of the tipsection 124 relative to a surface 133 of the heart cavity 132 can alsobe displayed on the graphical user interface 110.

In use, the tip section 124 of the catheter 104 can be inserted into aheart cavity 132 of the patient 102. Based on a signal received by thecatheter interface unit 108 from the magnetic position sensor 130 (thereceived signal being used to determine the location of the tip section124), the displayed view of the three-dimensional model 134 on thegraphical user interface 110 can change automatically in response tomovement of the tip section 124 within the heart cavity 132. Forexample, an orientation of the three-dimensional model 134 displayed onthe graphical user interface 110 can be updated based on the location(e.g., changes in location) of the tip section 124 relative to thesurface 133 of the heart cavity 132. Additionally, or alternatively, asize of the three-dimensional model 134 displayed on the graphical userinterface 110 can be updated (e.g., based on a speed of location changesof the tip section 124). Because the display of the three-dimensionalmodel 134 on the graphical user interface 110 can be responsive to thelocation of the tip section 124 in the heart cavity 132, the display ofthe three-dimensional model 134 can be automatically adjusted as thephysician manipulates the handle 120 to deflect the distal portion 128of the catheter shaft 122 to move the tip section 124 of the catheter104 relative to desired diagnostic and/or treatment location in theheart cavity of the patient 102.

In an exemplary treatment, the tip section 124 can be placed intocontact with a surface 133 of the heart cavity 132 and RF energy can bedirected from the tip section 124 to the surface 133 of the heart cavity132 to ablate tissue at some depth relative to the surface 133. Suchablations created by the tip section 124 along the surface 133 of theheart cavity can, for example, treat cardiac arrhythmia in patients withthis condition. However, the effectiveness of ablations created usingthe tip section 124 along the surface 133 of the heart cavity 132 can bedependent upon location of the ablations. Accordingly, automaticallyadjusting display views of the three-dimensional model 134 of the heartcavity, according to the methods described herein, can be useful for theefficient and effective mapping of the heart and/or efficient andeffective delivery of ablation treatment to treat cardiac arrhythmia.

The three-dimensional model 134 of the heart cavity 132 is stored on thestorage medium 111, along with instructions executable by the processingunit 109 to display a display view 136 of the three-dimensional model134 on the graphical user interface 110. The instructions stored on thestorage medium 111 and executable by the processing unit 109 to displaythe display view of the three-dimensional model 134 can be, for example,an application built using Visualization Toolkit, an open-source 3Dcomputer graphics toolkit, available at www.vtk.org.

FIG. 5 is a schematic representation of the display view 136 of thethree-dimensional model 134 projected onto the viewing window 138displayed on the graphical user interface 110. It should be understoodthat the three-dimensional model 134 can be stored in a memory such asthe storage medium 111 (FIG. 1). It should be further understood thatprojection of the three-dimensional model 134 can be carried out by theprocessing unit 109 (FIG. 1) executing computer-executable instructionsstored on the storage medium 111 (FIG. 1).

Referring to FIGS. 4 and 5, in instances in which the graphical userinterface 110 is a two-dimensional display, the three-dimensional model134 can be projected to a viewing window 138 of an image plane 140 toform an image having a center of projection 141. The image plane 140 cancorrespond to a plane of the two-dimensional display of the graphicaluser interface 110, the viewing window 138 can correspond to a field ofview of the two-dimensional display of the graphical user interface 110,and the center of projection 141 can correspond to the point of view ofa user viewing the image on the graphical user interface 110.Accordingly, the image formed by projecting the display view 136 of thethree-dimensional model 134 on the viewing window 138 can correspond toa specific orientation of the three-dimensional model 134 displayed onthe graphical user interface 110.

One or more features (e.g., point-of-view and size) of the display view136 forming the basis of the projection of the three-dimensional model134 onto the viewing window 138 on the graphical user interface 110 canbe a function of at least the position of the image plane 140 relativeto the three-dimensional model 134, the size of the viewing window 136on the image plane 140, and the distance between the viewing window 136and the center of projection 141. For example, movement of the imageplane 140 can result in corresponding movement of the display view. Asthe tip section 124 is moved within the heart cavity 132, the position(e.g., translation, orientation, or both) of the image plane 140 canchange relative to the three-dimensional model 134 and/or the size ofthe viewing window 136 on the image plane 140 can change, resulting incorresponding changes in one or more of the point-of-view, location, andsize of the display view 136 of the three-dimensional model 134displayed on the graphical user interface 110. Additionally, oralternatively, as the tip section 124 is moved within the heart cavity132, the position of the center of projection 141 can change, resultingin corresponding changes in one or more of the point-of-view, location,and size of the display view 136 of the three-dimensional model 134displayed on the graphical user interface 110.

The computer executable instructions stored on the storage medium 111(FIG. 1) can cause the processing unit 109 (FIG. 1) to display thethree-dimensional model 134 on the display view 136 on the graphicaluser interface 110 according to one or more of the following exemplarymethods. Unless otherwise indicated or made clear from the context, eachof the following exemplary methods can be implemented using the system100 (FIG. 1) and/or one or more components thereof.

Referring now to FIG. 6, an exemplary method 160 of displaying athree-dimensional representation of a patient's heart cavity can includeobtaining 162 a three-dimensional model of the heart cavity of thepatient, receiving 164 a signal indicative of location of a catheter inthe heart cavity of the patient, determining 165 at least one geometricfeature of the three-dimensional model, determining 166 a display viewof the three-dimensional model of the heart cavity, and 168 displaying(e.g., on a graphical user interface such as the graphical userinterface 110 shown in FIG. 1) the display view of the three-dimensionalmodel of the heart cavity. As described in greater detail below,determining 166 the display view of the three-dimensional model can bebased on one or more of the received 164 location of the catheter, theat least one geometric feature of the three-dimensional model, and onone or more previously received locations of the catheter in the heartcavity. It should be appreciated that, although described below in thecontext of a heart cavity, the exemplary method 160 can be carried outto display a three-dimensional representation of other anatomicstructures of a patient such as, for example, the brain, the lungs, thesinuses, and/or other hollow anatomic structures of the patient throughwhich a catheter may be passed (e.g., for the purpose of diagnosis,treatment, or both).

In general, obtaining 162 the three-dimensional model of the heartcavity can include receiving and/or determining a three-dimensionalmodel of the heart cavity prior to the procedure in which the display ofthe three-dimensional model is being controlled.

Obtaining 162 the three-dimensional model of the heart cavity caninclude, for example, receiving a plurality of locations of a catheterwithin the heart cavity and mapping the received visited locations ofthe catheter on a known coordinate system. In such implementations, aboundary of the visited locations can represent the blood-tissueboundary within the heart cavity. The plurality of received locationscan be from the catheter being used as part of the exemplary method 160and/or from another catheter (e.g., used as part of a previousprocedure).

In certain implementations, obtaining 162 the three-dimensional model ofthe heart cavity can include receiving signals from a magnetic sensordisposed along a distal portion of a catheter (e.g., such as themagnetic sensor 130 described above) and building the three-dimensionalmodel based on catheter locations determined from the received magneticsensor signals. In addition, or in the alternative, the receivedplurality of locations of the catheter can be determined based onimpedance of the catheter, ultrasound, imaging (e.g., fluoroscopy)and/or other known methods of determining catheter position.

In some implementations, obtaining 162 the three-dimensional model ofthe heart cavity can include receiving one or more images (e.g.,computed tomography (CT) images, magnetic resonance imaging (MM) images,or both) of the heart cavity and registering the images to a coordinatesystem of the magnetic position sensor or other tracking sensor. Theseimages can be acquired, for example, prior to the procedure. It shouldbe appreciated, however, that these images can be additionally, oralternatively, acquired in real-time (e.g., using rotationalangiography).

In general, receiving 164 the signal indicative of the location of thecatheter in the heart cavity can include receiving a signal indicativeof the location of the catheter according to any of the methodsdescribed herein. In certain instances, receiving 164 the signalindicative of location of the catheter in the heart cavity can includereceiving a signal indicative of contact (e.g., indicative of force)between the catheter and the heart cavity. Further, as used herein, thelocation of the catheter refers to the location of a tip section of thecatheter (e.g., the tip section 124 of the catheter 104 of FIG. 2). Itshould be understood, however, that the location of the catheter caninclude the location of any predetermined portion of the catheter in theheart cavity.

Receiving 164 the signal indicative of the location of the catheter inthe heart cavity can include receiving the signal over a period of time.As a specific example, the signal indicative of the location of thecatheter can be a time-varying signal. By determining 166 the displayview based on the time-varying signal received over a period of time,the determined 166 display view can be based on one or more previouslyreceived locations of the catheter. By way of further explanation, oneor more previously received locations, as used herein, should beunderstood to include one or more locations of the catheter receivedprior to a current time-step associated with the determined 166 displayview. For example, the time-varying received 164 signal can be processed(e.g., by low-pass filtering the time-varying signal). The determined166 display view can be based on the processed time-varying signal and,thus, can be based on one or more previously received locations of thecatheter. Additionally, or alternatively, a display view can be based onthe time-varying received 164 signal and the display view itself can beprocessed (e.g., by low-pass filtering the display view) such that thedetermined 166 display view can be based on one or more previous displayviews and is therefore based on one or more previously receivedlocations of the catheter. In certain implementations, the parametersfor processing the time-varying received 164 signal and/or thedetermined 166 display view can vary with the distance moved by thecatheter.

Processing the time-varying signal can be useful, for example, forimproved perception of the display view on the graphical user interface.For example, processing the time-varying signal of the received catheterlocation can smooth out changes in the display view corresponding tochanges in location of the catheter. Through such smoothing, theresulting determined 166 display view can be more stable (e.g., lessshaky), as compared to display views updated based on an unprocessed,time-varying signal. Accordingly, processing the time-varying signal canbe useful for creating changes to the determined 166 display view at arate that is both rapid enough to keep pace with changes in catheterposition but slow enough to avoid large changes and/or many small rapidchanges to the display view that are more likely to interfere with thephysician's use of the three-dimensional model to position the catheter.

Determining 165 at least one geometric feature of the three-dimensionalmodel includes any one or more of the various, different determinationsdescribed in further detail below. Thus, for example, determining 165the at least one geometric feature of the three-dimensional model caninclude determining a surface-normal direction in an area of the heartcavity local to the received 164 location of the catheter. Additionally,or alternatively, determining 165 the at least one geometric feature ofthe three-dimensional model can include determining a thinnest directionof the three-dimensional model. Further, or instead, determining 165 theat least one geometric feature of the three-dimensional model can bebased on determining a bounding box with the smallest volume thatcontains the three-dimensional model. Each of these determinations ofthe at least one geometric feature is set forth below with respect tothe determination 166 of the display view.

In general, determining 166 the display view of the three-dimensionalmodel can be based on one or more previously received locations of thecatheter in the heart cavity. In certain implementations, determining166 the display view can be based on one or more previously displayedviews. For example, determining 166 the display view can include one ormore rules (e.g., a hierarchy of rules), such as any of the rulesdescribed in further detail below, that constrain (e.g., reduce orprevent) certain transitions that are likely to be disruptive to aphysician using the three-dimensional model to position the catheter. Incertain implementations, determining 166 the display view can include arule that prevents the determined 166 view from being rotated relativeto a previously displayed view (e.g., an immediately previouslydisplayed view) by greater than a predetermined threshold (e.g., greaterthan about 5 degrees) along a vertical axis of the three-dimensionalmodel. Additionally, or alternatively, determining 166 the display viewcan include a rule that limits the rotation of the determined 166 viewin one or more directions of rotation. For example, one or more of theroll and the pitch of the determined 166 view can be limited accordingto a predetermined rule.

In certain implementations, determination 166 of the display view can bebased on the determination 165 of the at least one geometric feature ofthe three-dimensional model. Determining 166 the display view based onat least one geometric feature of the three-dimensional model can, forexample, provide useful views during a medical procedure performed ontissue at the surface of an anatomic structure and, in addition or inthe alternative, can account for variations in angles (axial or lateral)of engagement between the catheter and tissue during such medicalprocedures. An exemplary medical procedure of this type includesdelivering energy to the surface of a heart cavity to create a lesion,during which it is generally desirable to view the catheter from thepoint of view of the surface facing the catheter, rather than from thepoint of view of the catheter toward the surface, and it is further, oralternatively, desirable to have a display view that automaticallycompensates for variations in angles of engagement between the catheterand tissue.

For example, as described in greater detail below, the geometric featurecan be a local geometric feature of the three-dimensional model in thevicinity of the catheter, and the determined 166 display view can beoriented relative to this local geometric feature. As another example,also described in greater detail below, the geometric feature can be aglobal geometric feature (e.g., an overall shape of thethree-dimensional model) of the heart cavity, and the determined 166display view can be oriented relative to this global geometric feature.Further, the determined 166 display view can be determined according tothe received 162 location of the catheter and a hierarchy of rules basedat least in part on the local geometric feature and the global geometricfeature.

Referring now to FIGS. 6 and 7, the at least one geometric feature canbe a surface-normal direction N in an area of the three-dimensionalmodel local to the received location of the catheter. For example, thesurface-normal direction N can be a weighted sum of respective normalvectors 170 of surface elements 172 of the three-dimensional modelwithin a threshold distance from the received location of the catheter.For example, the threshold distance can be less than about 1 cm radiusfrom a point, on the surface mesh of the three-dimensional model,closest to the received location of the catheter. It should beappreciated that a lower bound of the threshold distance is the finitesize including at least one normal vector.

In general, because the surface-normal direction N is a function of thereceived location of the catheter, the surface-normal direction Nchanges as the catheter moves relative to the surface of the heartcavity and, thus, relative to the surface represented in thethree-dimensional model of the heart cavity. Further, because thesurface-normal direction N is a function of local features in thevicinity of the received location of the catheter, determining 166 thedisplay view based on the surface-normal direction N can facilitateautomatically orienting the display view toward the most prominentfeatures of the model in the vicinity of the received location of thecatheter. For example, the determined 166 display view of thethree-dimensional model can be oriented at a fixed angle (e.g.,perpendicular or parallel) relative to the surface-normal direction N.

While the influence of local geometry on the surface-normal direction Ncan make the surface-normal direction N a useful parameter fordetermining 166 the display view, the surface normal direction Ncorresponding to certain local geometries may not be suitable for basingthe determined 166 display view. For example, the surface-normaldirection N of certain local geometries can extend in a direction thatwould produce a display view that violates one or more rules for thedetermined 166 display view. Accordingly, the surface-normal direction Ncan be used as at least one factor in determining whether the determined166 display view is to be based on a local geometric feature or on aglobal geometric feature of the three-dimensional model. As one example,the determined 166 display view can be based on a global geometricfeature of the three-dimensional model when a direction perpendicular tothe surface-normal vector N is inappropriate (e.g., violates one or morepredetermined display rules) for the determined 166 display view.

Referring now to FIGS. 6 and 8, a thinnest direction 174 of thethree-dimensional model 134 is an example of a global geometric featureof the three-dimensional model that can be used to determine 166 thedisplay view. For certain anatomic structures, such as certain heartcavities, the thinnest direction of the three-dimensional model is thedirection that, in general, provides the least context with respect tothe three-dimensional model. Accordingly, it can be advantageous toidentify the thinnest direction and specify an image plane perpendicularto the thinnest direction such that the point of view of the determined166 display view is parallel to the other two directions, which canprovide more context (e.g., in the form of anatomic landmarks, etc.) tothe physician.

In some implementations, a bounding box analysis can be used todetermine the thinnest direction 174. For example, a bounding box 176with the smallest volume that contains the three-dimensional model 134can be determined. The bounding box 176 defines a three-dimensionalcoordinate system 178. The thinnest direction 174 of the bounding box176 and, thus, the thinnest direction of the three-dimensional model134, can be determined based on the length of the bounding box 176 ineach dimension of the three-dimensional coordinate system 178. Forexample, the thinnest direction 174 of the bounding box 176 can bedetermined by generating three scalar values representing the normalizedlength of the bounding box in the direction of each respectiveorthogonal vector in the three-dimensional coordinate system 178,comparing the three scalar values to one another, and selecting adirection corresponding to one (e.g., the shortest) of the orthogonalvectors.

The determined 166 display view can be, for example, parallel to thethinnest direction 174. It should be appreciated, however, that thethree-dimensional model 134 can have two sides along the thinnestdirection 174. Accordingly, as described in greater detail below, thedetermined 166 display view can be parallel to the thinnest direction174 and further determined according to a visualization preference ofthe three-dimensional model 134.

While the thinnest direction 174 has been described as one example of aglobal geometric feature, other types of geometric features canadditionally or alternatively be used. For example, principal componentanalysis can be applied to the three-dimensional model 134. In general,such principal component analysis can facilitate identifying theorientation of the mass of the heart cavity and/or surface correspondingto the three-dimensional model 134. Thus, as compared to the boundingbox approach to identifying a global geometric feature, principalcomponent analysis can be less prone to being skewed by geometricfeatures of the three-dimensional model 134 that, while extensive, donot correspond to the salient features of the three-dimensional model134.

In implementations in which principal component analysis is used toidentify a global geometric feature of the three-dimensional model 134,the determined 166 display view can be parallel to the directionrepresenting the most mass of the heart cavity and/or surface. It shouldbe appreciated that this orientation can be advantageous for providingthe physician with the view of the three-dimensional model 134 that ismost likely to provide useful contextual information.

In certain instances, the three-dimensional model 134 of the heartcavity may not have a substantially distinct global geometric feature(e.g., such as a global geometric feature determined using a boundingbox analysis and/or a principal component analysis). As used herein, asubstantially distinct global geometric feature can include a featurethat exceeds other global geometric features by a threshold amount.Thus, for example, the three-dimensional model 134 can be substantiallysymmetrical (e.g., be sphere-like) such that, for example, bounding boxanalysis and/or principal component analysis produces three orthogonalvectors with approximately equal magnitudes. In such instances, thedetermined 166 display view can be oriented in a direction determinedbased on a local geometric feature of the three-dimensional model 134such as, for example, based on the surface normal direction according toany of the methods described herein.

While determining 166 the display view has been described as being basedon the received 164 location of the catheter and on one or morepreviously received locations of the catheter in the heart cavity, otherimplementations are additionally or alternatively possible. For example,determining 166 the display view can be based on the received locationof the catheter in an anatomic structure and on a defined surface of thethree-dimensional model. As a more specific example, determining 166 thedisplay view of the three-dimensional model can be based on the receivedlocation of the catheter relative to the defined surface of thethree-dimensional model (e.g., relative to a local geometric feature ofthe defined surface of the three-dimensional model such as any one ormore of the local geometric features described herein).

The defined surface of the three-dimensional model can represent, forexample, a blood-tissue boundary of an anatomic structure. Additionally,or alternatively, the defined surface can include a surface mesh of thethree-dimensional model. The surface mesh can be determined according toany of various different methods that are well known in the art andinclude, for example, methods based on a boundary formed by locationsvisited by the catheter. The surface mesh can also, or instead, bedetermined from a volumetric dataset, such as a volumetric dataset fromCT, MRI, or other imaging modalities. In such implementations,segmentation can be performed to identify the blood-tissue boundary, anda surface mesh can be fitted to that boundary.

While determining 166 the display view has been described as being basedon at least one geometric feature of the three-dimensional model, itshould be appreciated that determining 166 the display view can,additionally or alternatively, be based on a received indication ofcontact between the catheter and the tissue. The received indication ofcontact can be, for example, received from a force sensor disposed alongthe catheter tip and of any of various, different configurationswell-known in the art.

The display view determined 166 based on the received indication ofcontact can be at a predetermined orientation relative to the receivedindication of contact. As an example, the display view can be opposite aforce vector corresponding to the received indication of contact. Asanother non-exclusive example, the display view can be orthogonal tosuch a force vector.

The determined 166 display view can be, for example, based solely on thereceived indication of contact. Thus, in an exemplary implementation,the determined 166 display view can remain constant while the catheteris not in contact with tissue. Continuing with this exemplaryimplementation, upon detecting reengagement of the catheter with tissue(e.g., through a new received indication of contact), the determined 166display view can be updated.

Additionally, or alternatively, the determined 166 display view can bebased on a combination of the received indication of contact and thesurface normal N local to the received 164 location of the catheter. Forexample, the determined 166 display view can be based on the receivedindication of contact when there is a received indication of contact andbased on the surface normal N when there is no received indication ofcontact (e.g., when the catheter is not in contact with tissue).Further, or instead, the determined 166 display view based on thereceived indication of contact can override the display view based onthe surface normal N based on predetermined criteria.

In certain implementations, comparing the display view determined 166based on the received indication of contact to the display viewdetermined 166 based on the surface normal N can provide useful insightswith respect to the three-dimensional model, the received 164 locationof the catheter, or both. For example, comparing the display viewdetermined 166 based on the received indication of contact to thedisplay view determined 166 based on the one or more local geometricfeatures can provide an indication of how closely the three-dimensionalmodel and the received 164 locations of the catheter correspond to theirphysical analogs. More specifically, the display view based on thereceived indication of contact can be substantially equivalent to thedisplay view based on one or more local geometric feature when thethree-dimensional model and the catheter positions match their physicalanalogs. Accordingly, it should be appreciated that differences in thedisplay view based on the received indication of contact and the displayview based on one or more local geometric feature can be useful, forexample, for updating the three-dimensional model, the received 164locations of the catheter, or combinations thereof.

While determining 166 the display view has been described as being basedon anatomy (e.g., at least one geometric feature of thethree-dimensional model) and/or based on a received indication ofcontact, it should be appreciated that, more generally, determining 166the display view can be based on any one or more methods describedherein for determining the point on the surface that is closest to thecatheter.

As an example, the determined 166 display view can, additionally oralternatively, be based on a change in one or more electrical signals(e.g., change in impedance) associated with one or more respectivesensors (e.g., electrodes) disposed along the catheter. In suchimplementations, a change in electrical signal can be an indication ofcontact. Continuing with this example, a change in one or moreelectrical signals associated with multiple different sensors can beindicative of contact as well as a direction of contact.

As another example, the determined 166 display view can be, additionallyor alternatively, based on an imaging modality that can detect tissue.For example, one or more ultrasound transducers can be fitted onto thecatheter to provide feedback regarding the point on the surface that isclosest to the catheter. In such configurations, the point on thesurface that is closest to the catheter can be visually or automaticallydiscernible from the ultrasound image.

While determining 166 the display view can be based on a local geometricfeature and/or a global geometric feature, determining 166 the displayview can, additionally or alternatively, be based on at least onevisualization preference for displaying the three-dimensional model. Forexample, a rule based hierarchy, such as a hierarchy based on a localgeometric feature and a global geometric feature, can be further basedon at least one visualization preference.

As used herein, the term “visualization preference” should be understoodto be broadly defined to include a display rule that is not directlybased on a local geometric feature or a global geometric feature. Forexample, a visualization preference can be predetermined (e.g., througha received user input) and/or determined based on previous display viewof the three-dimensional model. In general, a visualization preferencecan reduce the likelihood that the determined 166 display view will beunacceptable and/or disruptive to a physician using thethree-dimensional model to visualize a procedure that requires moving acatheter in the heart cavity.

Returning to the example of determining 166 the display view based onthe thinnest direction 174 of the three-dimensional model 134,determining 166 the display view can further include a visualizationpreference in which, of the two possible sides of the three-dimensionalmodel 134 to display, the side of the three-dimensional model 134closest to a previously displayed view (e.g., immediately previouslydisplayed view) of the three-dimensional model 134 is preferred. Thatis, unless this visualization preference is overridden by another rulein a hierarchy of rules, the display view will be oriented perpendicularto the thinnest direction 174 and along the side of thethree-dimensional model 134 closest to the previously displayed view ofthe three-dimensional model 134. Such a display rule can, for example,reduce the likelihood that the determined 166 display view will resultin an unacceptably large change in the display view that would bedisruptive to the physician performing the procedure.

Determining 166 the display view can, further or instead, be at leastpartially based on a visualization preference including a preferredorientation of the three-dimensional model. For example, the preferredorientation can be an orientation similar to or the same as anorientation obtained using a visualization technique (e.g., x-ray). Sucha preferred orientation can be useful, for example, for presenting anexpected or familiar orientation of the three-dimensional model to thephysician.

In certain implementations, determining 166 the display view can be atleast partially based on a visualization preference including a receiveduser input. For example, the physician can provide an input through anexternal device (e.g., a keyboard, a mouse, and/or a graphical userinterface) to specify a visualization preference according to thephysician's preference. In certain implementations, this input can beprovided by the physician before the procedure. In some implementations,this input can be provided by the physician during the procedure.

Determining 166 the display view can further, or alternatively, be basedat least in part on a relative orientation of a geometric feature (e.g.,a global geometric feature) to the at least one visualizationpreference. As an example, the determined 166 display view can be basedon snapping to a display view that incorporates a visualizationpreference. This can be understood, for example, by considering animplementation in which a display view based on a global geometricfeature results in two possible display views (e.g., on opposite sidesof the three-dimensional model) and the determined 166 display viewincludes selecting, from the two possible display views, the displayview that is closest to the previously displayed display view. Thus, incertain instances, determining 166 the display view based at least inpart on a relative orientation of a geometric feature to a visualizationpreference can advantageously reduce the likelihood of disorienting aphysician using the three-dimensional model as part of a procedure.

Referring now to FIGS. 5 and 6, displaying 168 the display view caninclude displaying a two-dimensional display of the display view of thethree-dimensional model. For example, the display view 136 can form abasis for projecting the three-dimensional model 134 onto a viewingwindow 138 defined in an image plane 140, which can correspond to agraphical user interface (e.g., the graphical user interface 110 in FIG.4).

In certain implementations, determining 166 the display view can includeadjusting a size of the three-dimensional model as projected onto theviewing window, and displaying 168 the display view can includedisplaying a projection of the three-dimensional model onto thegraphical user interface according to the determined size. For example,adjusting the size of the three-dimensional model projected onto theviewing window can be based on a size of the viewing window on an imageplane, a relative position of the image plane to the three-dimensionalmodel, and a relative position between the viewing window and a centerof projection for the three-dimensional model. In general, it should beappreciated that any one or more of these parameters can be varied toachieve a specific size of the projection of the three-dimensional modelonto the viewing window. As used herein, the size of the projection ofthe three-dimensional model onto the viewing window is also referred toas a zoom magnitude.

For example, at least one dimension (e.g., the width, the height, orboth) of the viewing window 138 can be a fixed percentage of a dimension(e.g., a maximum width, a maximum height, a maximum thickness) of thethree-dimensional model projected onto the image plane 140. Thispercentage or multiple can be, in certain instances, about 20-30 percentlarger than the projection of the determined display view of thethree-dimensional model onto the viewing window. It should be readilyappreciated, however, that other percentages or multiples areadditionally, or alternatively, possible.

Implementations in which at least one dimension of the viewing window138 is a fixed percentage larger than a dimension of the projection ofthe three-dimensional model can be useful, for example, for providingthe physician with context for the displayed 168 display view of thethree-dimensional model. That is, by displaying 168 the display view ofthe three-dimensional model such that a maximum dimension of thethree-dimensional model is less than a dimension of the viewing window,one or more boundaries of the three-dimensional model can be displayed168 on the graphical user interface. Such visible boundaries can, incertain instances, serve as visual cues to the physician regardingorientation of the displayed 168 three-dimensional model.

In some implementations, displaying 168 the display view of thethree-dimensional model can be based on a displacement speed of thecatheter. It should be appreciated that the displacement speed of thecatheter can be determined, for example, based on changes in receivedlocation of the catheter as a function of time. Given that thedisplacement speed can be a time-varying signal, it should be furtherappreciated that any of the methods described herein as being based ondisplacement speed can include filtering (e.g., low-pass filtering) thedisplacement speed.

In general, displaying 168 the display view of the three-dimensionalmodel can include changing the size of the three-dimensional model onthe viewing window, and, thus, on the graphical user interface, as thedisplacement speed of the catheter changes. In some implementations,displaying 168 the display view can include changing the size of theprojection of the three-dimensional model onto the viewing window ininverse relationship to the displacement speed of the catheter. Forexample, in instances in which the displacement speed of the catheter isrelatively high, the size of the three-dimensional model on the viewingplane can be made to be relatively small such that rapid changes can bemade to the display 168 of the three-dimensional model in response torapid changes in the displacement of the catheter. Continuing with thisexample, in instances in which the displacement of the catheter isrelatively low and thus updates to the displayed 168 view are alsorelatively slow, the size of the three-dimensional model on the viewingplane can be relatively large. This can be useful, for example, forfacilitating observation of a specific area of the three-dimensionalmodel by the physician, who may be moving the catheter slowly to observean area of interest in the three-dimensional model 134.

Additionally, or alternatively, displaying 168 the zoom magnitudeassociated with the display view can be based on the received 164catheter location including an indication of contact. That is, uponreceiving an indication of contact, the zoom magnitude can be increasedto provide a physician with a more detailed view of the area of thecontact. In certain instances, the indication of contact can include anindication of force, and the zoom magnitude can be increased ordecreased based on the indication of force. As an example, the zoommagnitude can be increased in response to the indication of force (e.g.,with zoom magnitude increasing with increasing force).

It should be appreciated that while displaying 168 the determined 166display view of the three-dimensional model has been described withrespect to a two-dimensional display, the methods described herein areadditionally, or alternatively, applicable to other types of displays.For example, all manner and methods of displaying 168 the determined 166display view of the three-dimensional model to a three-dimensionalgraphical user interface are within the scope of the present disclosure.Examples of such three-dimensional displays to which the determined 166display view of the three-dimensional model can be displayed 168 caninclude one or more of an augmented reality environment and a virtualreality environment.

Referring now to FIG. 9, an exemplary method 190 of displaying athree-dimensional representation of a patient's heart cavity can includeobtaining 192 a three-dimensional model of the heart cavity of thepatient, receiving 194 a signal indicative of location of a catheter inthe heart cavity of the patient, determining 196 a trajectory of displayviews of the three-dimensional model of the heart cavity, and displaying198 display views of the three-dimensional model of the heart cavity ona graphical user interface, according to the determined trajectory.Determining 196 the trajectory of the display views of thethree-dimensional model can be based at least in part on the received194 location of the catheter and on one or more previously receivedlocations of the catheter in the heart cavity. It should be appreciatedthat, although described below in the context of a heart cavity, theexemplary method 190 can be carried out to display a three-dimensionalmodel of other anatomic structures of a patient such as, for example,the brain, the lungs, the sinuses, and/or other hollow anatomicstructures of the patient through which a catheter may be passed for thepurpose of diagnosis and/or treatment.

Obtaining 192 the three-dimensional model of the heart cavity of thepatient can include any one or more methods of obtaining athree-dimensional model described herein. Thus, for example, obtaining192 the three-dimensional model can include receiving a plurality oflocations of a catheter within the heart cavity and mapping the receivedlocations according to any one or more of the methods described herein.In addition, or in the alternative, obtaining 192 the three-dimensionalmodel of the heart cavity can include receiving one or more datasets ofthe heart cavity, optionally segmenting them to form a surface mesh, andregistering the datasets to a coordinate system according to any one ormore of the methods described herein.

Receiving 194 the signal indicative of the location of the catheter inthe heart cavity of the patient can include any one or more of themethods of receiving such a signal described herein. Accordingly, thereceived 194 signal can include a signal based on a magnetic positionsensor (e.g., magnetic position sensor 130 described above). Further, orin the alternative, the received 194 signal can include or be derivedfrom a time-varying signal such as, for example, a signal from amagnetic position sensor.

Determining 196 the trajectory of the display views can, in general, bebased on the received 194 location of the catheter and on one or morepreviously received locations of the catheter in the heart cavity. Forexample, determining 196 the trajectory of the display views can bebased on a time-varying received 194 signal over a period of time. Anexample of determining 196 the trajectory of the display views,therefore, can include processing (e.g., low-pass filtering) thetime-varying signals and/or the display views based on the time-varyingsignal received 194 over a period of time.

Processing display views determined based on a time-varying signalreceived 194 over a period of time can result in a trajectory of thedisplay views. In addition, or as an alternative, determining 196 thetrajectory of the display views can be based one or more previouslydisplayed views. Thus, as used herein, the trajectory of the displayviews should be understood to include trend information related to thedisplay views such that the next display view can be determined based onthe trend information. For at least this reason, a person of ordinaryskill in the art will understand that, as compared to display viewsbased on an unprocessed signal indicative of catheter location, thedetermined 196 trajectory of the display views can be used as the basisof a more stabilized display of the three-dimensional model. As usedherein, a stabilized display of the three-dimensional model is one that,as compared to an unstabilized display or less stabilized display,exhibits fewer and less rapid changes and therefore appears less shaky.

In certain implementations, determining 196 the trajectory of displayviews can be based on an analyzed shape of the three-dimensional model.For example, the analysis of the three-dimensional model can includeanalyzing a portion of the three-dimensional model local to the received194 signal indicative of the current location of the catheter. Thislocal analysis of the three-dimensional model can, in some instances,include analyzing a local feature of the three-dimensional model. Inaddition, or in the alternative, the analysis of the three-dimensionalmodel can include analyzing one or more global features of thethree-dimensional model. It should be appreciated that the analysisbased on local and/or global features of the three-dimensional model caninclude any one or more of the analyses based on local and/or globalfeatures described herein.

In some implementations, determining 196 the trajectory of the displayviews can be based on one or more visualization preferences. Exemplaryvisualization preferences include any one or more of the visualizationpreferences described herein and, thus, may include a preferredorientation of the three-dimensional model.

Displaying 198 display views of the three-dimensional model of the heartcavity on a graphical user interface can be based on any one or more ofthe methods described herein. As an example, displaying 198 displayviews of the three-dimensional model of the heart cavity can includeprojecting the three-dimensional model onto a viewing plane defined inan image plane. It should be appreciated that the orientation of thethree-dimensional model in this projection can be based on thedetermined 196 trajectory of display views.

Referring now to FIG. 10, an exemplary method 200 of controlling adisplay of a three-dimensional model of an anatomic structure of apatient can include obtaining 202 the three-dimensional model of theanatomic structure of the patient, receiving 204 a signal indicative ofa location of a medical device in the anatomic structure, selecting 206a display rule, from a plurality of display rules, for specification ofan orientation of the three-dimensional model and an image plane,specifying 208 a the image plane, specifying 208 b the orientation ofthe three-dimensional model, and displaying 210 at least a portion of aprojection of the three-dimensional model (e.g., in the specifiedorientation and on the specified image plane) on a graphical userinterface. Examples of the anatomic structure can include, withoutlimitation, a heart cavity, the brain, the lungs, sinuses, and/or otherhollow anatomic structures of the patient through which a catheter maybe passed for the purpose of diagnosis and/or treatment. As described ingreater detail below, specifying 208 a the image plane and/or specifying208 b the orientation of the three-dimensional model can be based atleast in part on the selected 206 display rule.

Obtaining 202 the three-dimensional model can include any one or moremethods of obtaining a three-dimensional model described herein. As anexample, obtaining 202 the three-dimensional model can include receivinga plurality of locations of a medical device (e.g., any one or more ofthe medical devices described herein) within the anatomic structure andmapping the received visited locations according to any one or more ofthe methods described herein. Further, or instead, obtaining 202 thethree-dimensional model of the anatomic structure can include receivingone or more images of the anatomic structure and registering the imagesto a coordinate system according to any one or more of the methodsdescribed herein.

Receiving 204 the signal indicative of the location of the catheter inthe anatomic structure of the patient can include any one or more of themethods of receiving such a signal described herein. Accordingly, thereceived 204 signal can include a signal based on a magnetic positionsensor (e.g., magnetic position sensor 130 described above). Inaddition, or in the alternative, the received 204 signal can include atime-varying signal.

Selecting 206 a display rule, in general, can include selecting thedisplay rule from the plurality of display rules. The plurality ofdisplay rules can include predetermined display rules and/or displayrules based on inputs of a physician's preference. The selected 206display rule can, as described in greater detail below, form a basis forthe orientation of the three-dimensional model and the image plane fordisplaying 210 the projection of the three-dimensional model on thegraphical user interface. Accordingly, it should be appreciated that anyhierarchy of display rules described herein is provided by way ofexample, and not limitation, of achieving automated control of a displayof the three-dimensional model of the anatomic structure during themedical procedure. Further, it should be appreciated that the selection206 of the display rule from the plurality of display rules can, overthe course of a medical procedure, reduce the amount of manualadjustment of the three-dimensional model required during the medicalprocedure, thus requiring less attention from the physician andimproving efficiency of medical procedures.

Selecting 206 the display rule can be based at least in part on thereceived location of the medical device relative to the anatomicstructure. In general, selecting 206 the display rule can includedetermining whether the applicable display rule is based on the receivedlocation of the medical device or based at least in part on the shape ofthe three-dimensional model. More specifically, a local display rule canbe based at least in part on the received location of the medical devicerelative to the three-dimensional model, and a global display rule canbe based at least in part on the shape of the three-dimensional model.In such instances, selecting 206 the display rule can include choosingthe local display rule unless, based on the received location of thecatheter, the local display rule is inappropriate, in which case theglobal display rule is chosen. The local display rule and the globaldisplay rule can be any one or more of the local display rules and theglobal display rules described herein.

Referring now to FIGS. 10 and 11, exemplary methods of selecting 206 thedisplay rule are, for the sake of clarity, described with respect to aschematic representation of a location 212 of the tip section 124 of thecatheter 104 relative to the three-dimensional model 134 of the heartcavity 132. It should be appreciated, however, that these exemplarymethods of selecting 206 the display rule can be additionally, oralternatively, applicable to other types of medical devices,three-dimensional models, and/or anatomic structures.

A spatial reference 214 can be defined with respect to thethree-dimensional model 134. In certain implementations, the spatialreference 214 can include a reference axis (e.g., as specified by auser). In such implementations, the spatial reference 214 can be alignedwith a superior-inferior axis defined by the three-dimensional model.The spatial reference 214 aligned with a superior-inferior axis canfacilitate, as an example, preferentially orienting thethree-dimensional model 134 in a superior-inferior direction (e.g., withthe projection of the three-dimensional model orienting in the “up”direction on the viewing window). This can be advantageous, in certainimplementations, for displaying 210 the three-dimensional model 134according to views consistent with other types of diagnostic imaging(e.g., x-ray).

Additionally, or alternatively, the spatial reference 214 can include auser input (e.g., received from one or more of a keyboard, a mouse, anda graphical user interface). By way of example and not limitation, theuser input can include an indication of a predetermined preferredlocation and/or direction of the reference axis.

The location 212 of the tip section 124 of the catheter 104 can be basedat least in part on the received 204 signal indicative of location ofthe tip section 124 of the catheter 104. A person of ordinary skill inthe art will appreciate, therefore, that the selected 206 display rulecan change as the location 212 of the tip section 124 changes duringtreatment. Such changes in the selection 206 of the display rule canfacilitate automatically updating the display 210 of the projection ofthe three-dimensional model 134 to provide the physician withinformative views of the three-dimensional model. Informative views ofthe three-dimensional model can include, by way of example and notlimitation, views that are relatively unobscured, are in an expectedorientation (e.g., consistent with an anatomic pose of the patient),and/or provide the physician with context with respect to the location212 of the tip section 124 relative to the three-dimensional model 134.

A local direction vector 216 can be determined based on the received 204signal indicative of the location of the catheter 204. In certainimplementations, the local direction vector 216 can originate from thereceived 204 location of the catheter 104. Thus, in suchimplementations, the local direction vector 216 can point in a directionaway from the catheter 204 and toward a surface of the three-dimensionalmodel 134.

In general, selecting 206 the display rule can include comparing thelocation 212 of the catheter to a prohibited region 218 at leastpartially defined by the three-dimensional model. Based at least in parton this comparison, the local rule or the global rule can be selected.In instances in which the comparison results in a switching between thelocal rule and the global rule, the transition can be a gradualtransition to facilitate a smooth transition of the display view on thegraphical user interface. It should be appreciated that the prohibitedregion 218 represents a location 212 or a collection of locations 212 ofthe catheter in which selecting a local display rule can result in aview or a collection of views that have an increased likelihood of beingunacceptable to the physician as being uninformative and/ordisorienting. One example, among several, of such an uninformativeand/or disorienting view corresponding to the prohibited region 218 is aview of the three-dimensional model 134 directly along the spatialreference 214 (e.g., along a superior-inferior axis).

The local direction vector 216 can be based at least in part ondirection vectors normal to a surface of the three-dimensional model 134in an area local to the received 204 location of the catheter 104. Forexample, the local direction vector 216 can be based at least in part ona surface normal direction determined according to any one or more ofthe methods described herein. Accordingly, the local direction vector216 can be a weighted sum of direction vectors normal to a surface ofthe three-dimensional model 134 in an area local to the received 204location of the catheter 104.

The prohibited region 218 can be at least partially defined by thethree-dimensional model 134. For example, the prohibited region 218 canbe at least partially defined by a center of mass of a volume of fluidrepresented by the three-dimensional model. As a more specific example,the prohibited region 218 can be substantially symmetric about at leastone plane containing the center of mass. Additionally, or alternatively,the prohibited region 218 can be substantially symmetric about thespatial reference 214 (e.g., about a superior-inferior axis).

In certain implementations, the prohibited region 218 can include adouble-infinite right cone. As used herein, the term “double-infiniteright cone” includes two right circular cones (e.g., of the same size)placed apex to apex. The opening angle of each cone of thedouble-infinite right cone can be greater than about 5 degrees and lessthan about 90 degrees. The base of each cone of the double-infiniteright cone can be, for example, perpendicular to a reference axis inimplementations in which the spatial reference 214 includes thereference axis. In some implementations, the apices of the two rightcircular cones are at a center of mass of a volume of fluid representedby the three-dimensional model.

In implementations in which the prohibited region 218 includes adouble-infinite right cone, comparing the location 212 of the catheterto the prohibited region 218 includes determining whether location 212of the catheter is within either lobe of the double-infinite right cone.Continuing with this example, selecting 206 the display rule can includeselecting the local rule or the global rule based on whether thelocation 212 of the catheter is within the double-infinite right cone.For example, the global rule can be selected 206 if the location 212 ofthe catheter is within a boundary of the prohibited region 218.Additionally, or alternatively, the local rule can be selected 206 ifthe location 212 of the catheter is a predetermined distance beyond aboundary of the prohibited region. This predetermined distance can be,for example, a transition region in which a combination of the localrule and the global rule is selected if the location 212 of the catheteris within the transition distance. Such a combination can be useful, forexample, for producing smooth transitions resulting from moving thelocation 212 of the catheter into and out of the prohibited region 218.As an example, a relative weighting of the local rule to the global rulecan be varied (e.g. substantially linearly) as a function of distancefrom the location 212 of the catheter to the prohibited region 218.

The prohibited region 218 including the double-infinite right cone canbe advantageous, for example, for implementing a rule hierarchy based onsymmetry in multiple directions. Additionally, or alternatively, thedouble-infinite right cone can be advantageous for displaying thethree-dimensional model from the point of view of the catheter 104.While the prohibited region 218 is described as including adouble-infinite right cone, it should be appreciated that other shapesof the prohibited region 218 are additionally, or alternatively,possible. For example, for certain anatomic structures, the prohibitedregion 218 can be appropriately shaped as a single cone, a cylinder,and/or a sphere.

If the local rule is selected 206 as the display rule, the specified 208a image plane can be perpendicular to the axis defined by the localdirection vector 216. The image plane can be, for example, any one ormore of the image planes described herein. Thus, the image plane can bea plane corresponding to a plane of a two-dimensional display of any oneor more graphical user interfaces described herein. Additionally, oralternatively, if the local rule is selected 206, the pitch of the imageplane relative to an axis (e.g., the spatial reference 214) can belimited by a predetermined amount. Further, or instead, if the localrule is selected 206, the roll of the viewing window can be limited by apredetermined amount relative to an axis (e.g., the spatial reference214).

Continuing with implementations in which the local rule is the selected206 display rule, the specified 208 a image plane can be outside of asurface boundary of the three-dimensional model 134. Such a position ofthe image plane relative to the three-dimensional model 134 can beuseful, for example, for providing context to the displayed 210projection of the three-dimensional model. Such context can facilitatethe physician's ability to identify anatomic features in thethree-dimensional model 134 and, in some instances, facilitatepositioning the catheter 104 in the heart cavity.

Continuing further with implementations in which the local rule isselected 206 as the display rule, the specified 208 a image plane can bebased in part on the direction of the local direction vector 216. Morespecifically, the specified 208 a image plane can be perpendicular tothe local direction vector 218. For example, the specified 208 a imageplane can be positioned relative to the local direction vector 216 suchthat the point of view of the displayed 210 projection of thethree-dimensional model 134 is from the point of view of the tip section124 of the catheter 104. Such a position of the specified 208 a imageplane relative to the local direction vector 216 can facilitate viewingthe three-dimensional model 134 of the anatomic structure from the pointof view of the tip section 124 of the catheter 104. It should beappreciated that such a point of view can be advantageous for providingan intuitive coordinate system for the physician to manipulate the tipsection 124 of the catheter 104 within the anatomic structure.

If the local rule is selected 206 as the display rule, specifying 208 bthe orientation of the three-dimensional model 134 can include orientinga portion of the three-dimensional model 134 to extend in apredetermined preferred direction. As an example, in implementations inwhich the spatial reference 214 is a superior-inferior axis of thethree-dimensional model 134, specifying 208 b the orientation of thethree-dimensional model 134 can include orienting a superior portion ofthe three-dimensional model 134 in the superior direction of thesuperior-inferior axis. This preferred orientation can be convenient forproviding the physician with a familiar orientation of the anatomicstructure represented in the three-dimensional model 134. Additionally,or alternatively, the portion of the three-dimensional model 134 and/orthe predetermined preferred direction can be received as inputs throughany one or more of the input devices described herein. It should beappreciated that, in use, these inputs can be useful for creatingcustomized views of the anatomic structure represented by thethree-dimensional model 134. Customization of this type can be useful,for example, for providing the physician with specific views thatcorrespond to the physician's preferences and/or are necessitated by theparticular medical procedure.

If the global rule is selected 206 as the display rule, specifying 208 athe image plane and/or specifying 208 b the orientation of thethree-dimensional model 134 can include determining a thinnest directionof the three-dimensional model 134 of the anatomic structure. It shouldbe appreciated that such a determination of the thinnest direction ofthe three-dimensional model 134 can include any one or more of themethods described herein. For example, the determination of the thinnestdirection of the three-dimensional model 134 can be based on principalcomponent analysis and/or a bounding box analysis.

Continuing with implementations in which the global rule is selected 206as the display rule, specifying 208 a the image plane can includespecifying 208 a the image plane in a plane perpendicular to an axisdefined by the thinnest direction and/or an axis defined by thedirection representing the least amount of mass in the three-dimensionalmodel 134. Accordingly, in such implementations, the image plane can beparallel to the other directions of the coordinate system of thethree-dimensional model 134. Because the thinnest direction and/or thedirection representing the least amount of mass in the three-dimensionalmodel is generally the direction that provides the physician with theleast amount of context with respect to the three-dimensional model 134,specifying 208 a the image plane parallel to one of the other directionsin the coordinate system can be advantageous for providing the physicianwith context with respect to the three-dimensional model 134. Further,or in the alternative, the specified 208 a image plane can be outside ofa surface boundary of the three-dimensional model 134, which can beuseful for providing additional or alternative context to the physician.

Continuing further with implementations in which the global rule isselected 206 as the display rule, specifying 208 b the orientation ofthe three-dimensional model 134 can include orienting a portion of thethree-dimensional model 134 in a preferred direction relative to thespatial reference 214. Such orientation can include any one or moremethods described herein for orienting the three-dimensional model 134.Accordingly, it should be appreciated that the portion of thethree-dimensional model 134 and/or the preferred direction can bepredetermined (e.g., based on a received input according to any one ormore of the input devices described herein).

Displaying 210 the projection of the three-dimensional model 134 on agraphical user interface can be carried out according to one or more ofthe methods described herein. For example, displaying 210 the projectionof the three-dimensional model 134 can include determining a zoommagnitude. As another non-exclusive example, at least one dimension ofthe viewing window can be maintained at a fixed multiple of a dimensionof the three-dimensional model 134 in the image plane.

In certain implementations, the zoom magnitude can be based at least inpart on the determined displacement speed of the medical deviceaccording to any one or more of the methods described herein. Inexemplary implementations, therefore, the zoom magnitude can increase asthe displacement speed of the catheter 104 decreases.

Referring now to FIG. 12, an exemplary method 220 of controllingtwo-dimensional views of a three-dimensional anatomical model caninclude generating 222 a three-dimensional model of an anatomicstructure of a patient, displaying 224 (e.g., on a graphical userinterface) a projection of the three-dimensional model on a viewingwindow of an image plane, receiving 226 a signal indicative of alocation of the medical device in the anatomic structure, determining228 a displacement speed of the medical device in the anatomicstructure, and adjusting 230 a zoom magnitude based at least in part onthe determined displacement speed of the medical device. The exemplarymethod 220 can be carried out using any one or more of the devices andsystems described herein and can be applicable to visualization of anyof various, different medical devices during any of various, differentmedical procedures. Further, or instead, the anatomic structure of thepatient can be any anatomic structure described herein, with examplesincluding a heart cavity, the lungs, the brain, the sinuses, and/or anyanatomic structure through which a catheter can be moved.

Generating 222 the three-dimensional model of the anatomic structure ofthe patient can include any one or more of the methods described herein.Thus, for example, generating 222 the three-dimensional model should beunderstood to include methods based on received locations of the medicaldevice.

Displaying 224 the projection of the three-dimensional model on theviewing window of the image plane can include any one or more of themethods described herein. Similarly, receiving 226 the signal indicativeof the location of the medical device can include any one or more of themethods described herein. Therefore, examples of displaying 224 theprojection of the three-dimensional model and/or receiving 226 thesignal indicative of the location of the medical device can includemethods described with respect to FIGS. 4 and 5.

Determining 228 the displacement speed of the medical device in theanatomic structure can be based at least in part on the received 226location of the medical device. Additionally, or alternatively,determining 228 the speed of the medical device can include any one ormore of the methods described herein.

Adjusting 230 the zoom magnitude can include any of the methodsdescribed herein. As an example, adjusting 230 the zoom magnitude caninclude decreasing the size of the viewing window with decreasingdisplacement speed of the medical device. As an additional oralternative example, adjusting 230 the zoom magnitude can includeadjusting a field of view. In certain implementations, the field of viewcan decrease as the displacement speed decreases. In someimplementations, adjusting 230 the zoom magnitude can include adjustinga distance between the image plane and a center of projection.Additionally, or alternatively, adjusting 230 the zoom magnitude caninclude moving the viewing window and the center of projection (e.g.,together) relative to the three-dimensional model. More generally,adjusting 230 the zoom magnitude can include any one or more adjustmentsthat change the size of the projection of the three-dimensional model onthe graphical user interface.

The above systems, devices, methods, processes, and the like may berealized in hardware, software, or any combination of these suitable fora particular application. The hardware may include a general-purposecomputer and/or dedicated computing device. This includes realization inone or more microprocessors, microcontrollers, embeddedmicrocontrollers, programmable digital signal processors or otherprogrammable devices or processing circuitry, along with internal and/orexternal memory. This may also, or instead, include one or moreapplication specific integrated circuits, programmable gate arrays,programmable array logic components, or any other device or devices thatmay be configured to process electronic signals.

It will further be appreciated that a realization of the processes ordevices described above may include computer-executable code createdusing a structured programming language such as C, an object orientedprogramming language such as C++, or any other high-level or low levelprogramming language (including assembly languages, hardware descriptionlanguages, and database programming languages and technologies) that maybe stored, compiled or interpreted to run on one of the above devices,as well as heterogeneous combinations of processors, processorarchitectures, or combinations of different hardware and software. Inanother aspect, the methods may be embodied in systems that perform thesteps thereof, and may be distributed across devices in a number ofways. At the same time, processing may be distributed across devicessuch as the various systems described above, or all of the functionalitymay be integrated into a dedicated, standalone device or other hardware.In another aspect, means for performing the steps associated with theprocesses described above may include any of the hardware and/orsoftware described above. All such permutations and combinations areintended to fall within the scope of the present disclosure.

Embodiments disclosed herein may include computer program productscomprising computer-executable code or computer-usable code that, whenexecuting on one or more computing devices, performs any and/or all ofthe steps thereof. The code may be stored in a non-transitory fashion ina computer memory, which may be a memory from which the program executes(such as random access memory associated with a processor), or a storagedevice such as a disk drive, flash memory or any other optical,electromagnetic, magnetic, infrared or other device or combination ofdevices.

In another aspect, any of the systems and methods described above may beembodied in any suitable transmission or propagation medium carryingcomputer-executable code and/or any inputs or outputs from same.

It will be appreciated that the devices, systems, and methods describedabove are set forth by way of example and not of limitation. Absent anexplicit indication to the contrary, the disclosed steps may bemodified, supplemented, omitted, and/or re-ordered without departingfrom the scope of this disclosure. Numerous variations, additions,omissions, and other modifications will be apparent to one of ordinaryskill in the art. In addition, the order or presentation of method stepsin the description and drawings above is not intended to require thisorder of performing the recited steps unless a particular order isexpressly required or otherwise clear from the context.

The method steps of the implementations described herein are intended toinclude any suitable method of causing such method steps to beperformed, consistent with the patentability of the following claims,unless a different meaning is expressly provided or otherwise clear fromthe context. So for example performing the step of X includes anysuitable method for causing another party such as a remote user, aremote processing resource (e.g., a server or cloud computer) or amachine to perform the step of X. Similarly, performing steps X, Y and Zmay include any method of directing or controlling any combination ofsuch other individuals or resources to perform steps X, Y and Z toobtain the benefit of such steps. Thus method steps of theimplementations described herein are intended to include any suitablemethod of causing one or more other parties or entities to perform thesteps, consistent with the patentability of the following claims, unlessa different meaning is expressly provided or otherwise clear from thecontext. Such parties or entities need not be under the direction orcontrol of any other party or entity, and need not be located within aparticular jurisdiction.

Thus, while particular embodiments have been shown and described, itwill be apparent to those skilled in the art that various changes andmodifications in form and details may be made therein without departingfrom the spirit and scope of this disclosure and are intended to form apart of the invention as defined by the following claims.

1-21. (canceled)
 22. A method comprising: receiving a signal indicativeof a position of a catheter in a heart cavity of a patient; determininga geometric characteristic of a three-dimensional representation of theheart cavity; and determining a display view of the three-dimensionalrepresentation based, at least in part, on (i) the position of thecatheter in the heart cavity, (ii) one or more previous positions of thecatheter in the heart cavity, and (iii) the determined geometriccharacteristic of the three-dimensional model, wherein determining thedisplay view includes— processing the received signal such that atransition from a previous display view to the determined display viewis smooth and is perceived as continuous motion of the three-dimensionalrepresentation, and/or processing the display view such that thedetermined display view is based on one or more previous display views.23. The method of claim 22 wherein determining the at least onegeometric characteristic includes calculating, in the three-dimensionalrepresentation, a surface-normal direction in an area of the heartcavity local to the position of the catheter.
 24. The method of claim 23wherein the surface-normal direction is a function of the position ofthe catheter and local characteristics of the three-dimensionalrepresentation local to the position of the catheter such that thedisplay view automatically compensates for variations in angles ofengagement between the catheter and target tissue.
 25. The method ofclaim 22 wherein determining the at least one geometric characteristicincludes determining a thinnest direction of the three-dimensionalrepresentation.
 26. The method of claim 22 wherein determining the atleast one geometric characteristic is based on determining a boundingbox with a smallest volume that contains the three-dimensionalrepresentation.
 27. The method of claim 22, further comprisingdetermining at least one visualization preference of thethree-dimensional representation, wherein determining the display viewis further based, at least in part, on the at least one visualizationpreference.
 28. The method of claim 22 wherein determining the displayview is based, at least in part, on the received signal over a period oftime.
 29. The method of claim 22 wherein determining the display view isfurther based, at least in part, on analysis of a shape of thethree-dimensional representation of the heart cavity of the patient. 30.The method of claim 22 wherein determining the display view is furtherbased, at least in part, on visualization preferences.
 31. The method ofclaim 22, further comprising transmitting, to a graphical userinterface, the determined display view of the three-dimensionalrepresentation of the heart cavity.
 32. The method of claim 22, furthercomprising displaying, on a graphical user interface, the determineddisplay view of the three-dimensional representation of the heartcavity.
 33. The method of claim 32 wherein determining the display viewincludes adjusting a size of the three-dimensional representation asprojected onto a viewing window, and displaying the display viewincludes displaying a projection of the three-dimensional representationonto the graphical user interface according to the adjusted size.
 34. Amethod comprising: receiving, at a processing unit external to apatient, a signal indicative of a position of a catheter in a heartcavity of the patient; determining, at the processing unit, at least onegeometric characteristic of a three-dimensional representation of theheart cavity, wherein determining the at least one geometriccharacteristic includes calculating, independent of an orientation ofthe catheter, a surface-normal direction of the three-dimensionalrepresentation in an area of the heart cavity local to the position ofthe catheter; determining, at the processing unit, a display view of thethree-dimensional representation of the heart cavity based at least inpart on the position of the catheter in the heart cavity, on one or moreprevious positions of the catheter in the heart cavity, and on thegeometric characteristic of the three-dimensional representation; andtransmitting, from the processing unit to a graphical user interface,the display view of the three-dimensional representation of the heartcavity.
 35. The method of claim 34 wherein the surface-normal directionis a function of the position of the catheter and local characteristicsof the three-dimensional representation local to the position of thecatheter such that the display view automatically compensates forvariations in angles of engagement between the catheter and targettissue.
 36. The method of claim 34 wherein determining the at least onegeometric characteristic further includes determining a thinnestdirection of the three-dimensional representation.
 37. The method ofclaim 34, further comprising determining at least one visualizationpreference of the three-dimensional representation, wherein determiningthe display view is further based, at least in part, on the at least onevisualization preference.
 38. The method of claim 34 wherein determiningthe display view of the three-dimensional representation is based, atleast in part, on the received signal over a period of time and/or onone or more previous display views.
 39. The method of claim 34 whereindetermining the display view is further based, at least in part, onanalysis of a shape of the three-dimensional representation of the heartcavity of the patient.
 40. The method of claim 34 wherein determiningthe display view is further based, at least in part, on visualizationpreferences.
 41. The method of claim 34 wherein determining the displayview includes adjusting a size of the three-dimensional representationas projected onto a viewing window, and displaying the display viewincludes displaying a projection of the three-dimensional representationonto the graphical user interface according to the adjusted siz